Synthesis of telechelic anthraquinone‐functionalized polybutadiene via ROMP and study of its photo‐oxidation and UV crosslinking behaviors

Abstract

Telechelic anthraquinone‐functionalized polybutadiene (AQ‐PB‐AQ) was synthesized by ring opening metathesis polymerization to achieve homogeneous dispersion of AQ groups in the polymer matrix. It was observed that the AQ end groups act as a sensitizing group resulting in photo‐induced crosslinking and oxidation reaction at the olefin groups in the PB. The process was confirmed by comparing the polymer's mass loss and Fourier transform infrared (FTIR) spectra with those of telechelic diacetoxy‐functionalized PB (AcO‐PB‐OAc) which did not show any difference before and after ultraviolet irradiation. Homogeneity of the AQ groups in PB matrix results in rapid crosslinking of PB in a short period of time (<4 min) while a simple blend of AQ methyl ester in AcO‐PB‐OAc matrix did not show such behavior. Photo‐oxidative reaction has concurrently occurred during the crosslinking reaction. Generation of OH, OOH, and carbonyl groups in the matrix during the photo‐oxidation was verified by FTIR, elemental analysis, and water contact angle measurements. A plausible mechanism for the process was proposed in which the photo‐sensitized AQ groups abstract hydrogen from the PB chain to yield reactive radical species, initiating oxidative crosslinking, and degradation of PB or reduction of AQ to hydroanthraquinone species. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1249–1258

Photoactivities of Vitamin K Derivatives and Potential Applications as Daylight-Activated Antimicrobial Agents

“…Benzophenone and anthraquinone derivatives are aromatic ketones and widely used as photoinitiators in chemical reactions. − These chemicals mostly generate HO· and H 2 O 2 as the main ROS under UV irradiation , by undergoing a similar photoreaction process. The excited molecules can go intersystem crossing (ISC) with high efficiency to their triplet excited states (T 1 ), which then react with ground-state triplet oxygen ( 3 O 2 ) in the air to produce ROS. − Aromatic carbonyl and similar structures such as VK 1–3 compounds enable excellent UV absorption and indirect ISC, satisfying El-Sayed’s rules. − These VK compounds (Figure a) under photoirradiation can be excited from the ground state (S 0 ) to their multiple singlet excited states (S n ) that are very active and short-lived.…”

Monodisperse and Telechelic Polyethylenes Form Extended Chain Crystals with Ionic Layers

“…Alternatively, the functional groups could be placed at the ends of short linear PE chain of uniform molecular weight, thus enabling the alkyl segments to crystallize and produce layers of functional groups. − A previous study observed that the layered assembly of functional groups persists even after the melting of hydrocarbon chains when the PEs are functionalized with thymine groups on both ends. , Polymers with two reactive end groups, namely, telechelics, have been studied extensively as building blocks for block copolymers, thermoplastic elastomers or polymer networks, as well as surfactants, chain extenders, and cross-linkers . Telechelics with a PE backbone have been little studied, however, because of the difficulty in synthesizing these materials.…”